Visibility-Oriented Algorithms for Digital Terrain Models (Computer and Information Science)

定义了视点在曲面上的“可见区”。它包含可以通过不穿过曲面的线段连接到视点的所有点。原则上，可以计算出曲面上每个点的可见区。然而，在实践中，它的计算必须是近似的。本文研究了Delaunay三角化地形模型中n个顶点的可见区。本研究的一个主要目标是提高已有的隐线和隐面算法的平均性能。这是通过使用基于问题的独特特征的几种类型的启发式方法来实现的。将开发算法，以将产生的能见度图应用于观察点的位置：视线(电视、调频、雷达)通信和监视问题；定向和导航；数据压缩；以及提取重要的地形特征，如山脊和山谷。认为可见性模型的全局性为定义地形实体提供了一种有用的替代偏导数的方法。这项研究预计将对计算几何、地理信息系统和计算机通信等多个领域做出贡献。

The "visibility region" of a viewpoint on a surface is wll- defined. It contains all of the points that can be joined to the viewpoint by means of a line-segment that does not pass through the surface. In principle, the visibility region of every point on the surface can be computed. In practice, however, its computation must be approximated. In this research, the visibility regions of the n vertices of a Delaunay-triangulated terrain model are studied. A major goal of this research is to improve the average performance of known hidden-line and hidden- surface algorithms. This is accomplished by using several types of heuristics based on the unique characteristics of the problem. Algorithms will be developed to apply the resulting visibility maps to the location of observation points: to line-of-sight (television, fm, radar) communications and surveillance problems; to orientation and navigation; to data compression; and to the extraction of significant terrain features such as ridges and valleys. It is argued that the global nature of visibility model provides a useful alternative to partial derivatives for defining topographic entities. This research is expected to contribute to several areas including computational geometry, geographic information systems, and to computer communications.